Transcript Meningitis - Creighton University :: Medical School

Meningitis
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Bacterial
Viral ( aseptic)
TB
Fungal
Chemical
Parasitic
? Carcinomatous
Meningitis
• Definition
– Bacterial meningitis is an inflammatory
response to bacterial infection of the piaarachnoid and CSF of the subarachnoid space
• Epidemiology
– Incidence is between 3-5 per 100,000
– More than 2,000 deaths annually in the U.S.
– Relative frequency of bacterial species varies
with age.
Meningitis
• Epidemiology
– Neonates (< 1 Month)
• Gm (-) bacilli 50-60%
• Grp B Strep 20-40%
• Listeria sp. 2-10%
• H. influenza 0-3%
• S. pneumo 0-5%
Meningitis
• Epidemiology
– Children (1 month to 15 years)
• H. influenzae
40-60%
– Declining dramatically in many geographic
regions
• N. meningitidis 25-40%
• S. pneumo
10-20%
Meningitis
• Epidemiology
– Adults (> 15 years)
• S. pneumo
• N. Meningitidis
30-50%
10-35%
– Major cause in epidemics
• Gm (-) Bacilli
1-10%
– Elderly
• S. aureus
• H. influenzae
5-15%
1-3%
– >60 include Listeria, E. coli, Pseudomonas
Meningitis
• Pathogenesis
– Majority of cases are hematogenous in
origin
– Organisms have virulence factors that
allow bypassing of normal defenses
• Proteases
• Polysaccharidases
Meningitis
• Pathology and Pathogenesis
– Sequential steps allow the pathogen into the
CSF
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Nasopharyngeal colonization
Nasopharyngeal epithelial cell invasion
Bloodstream invasion
Bacteremia with intravascular survival
Crossing of the BBB and entry into the CSF
Survival and replication in the subarachnoid space
Meningitis
• Pathology
– Hallmark
• Exudate in the subarachnoid space
• Accumulation of exudate in the dependent areas of
the brain
• Large numbers of PMN’s
• Within 2-3 days inflammation in the walls of the
small and medium-sized blood vessels
• Blockage of normal CSF pathways and blockage of
the normal absorption may lead to obstructive
hydrocephalus
Meningitis
• Clinical Manifestations
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HA
Fever
Meningismus
Cerebral dysfunction
• Confusion, delirium, decreased level of
consciousness
– N/V
– Photophobia
Meningitis
• Clinical Manifestations – Nuchal rigidity
– Kernig’s
• Pt supine with flexed knee has increased pain with
passive extension of the same leg
– Brudzinski’s
• Supine pt with neck flexed will raise knees to take
pressure off of the meninges
• Present in 50% of acute bacterial meningitis cases
– Cranial Nerve Palsies
• IV, VI, VII
– Seizures
Meningitis
• Clinical Manifestations - Meningococcemia
– Prominent rash
• Diffuse purpuric lesions principally involving the
extremities
– Fever, hypotension, DIC
– History of terminal complement deficiency
– Classic findings often absent
• Neonates
• Elderly
Meningitis
Meningitis
• Diagnosis
– Assess for increased ICP
• Papilledema
• Focal neurologic findings
– Defer LP until CT scan or MRI obtained if any
of above present
– If suspect meningitis and awaiting
neuroimaging
• Obtain BC’s and start empiric Abx
Meningitis
Papilledema
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Obtain CT scan before lumbar puncture in patients
with:
Immunucompromised state
History of CNS disease
New onset seizures
Papilledema
Altered level of consciousness
Focal neurologic signs
• Obtain blood cultures and give empiric
antibiotics if LP is delayed
LP-CSF
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Tube # 1 Protein & Glucose
Tube # 2 Gram stain & Culture
Tube # 3 Cell count & differential
Tube # 4 Store ( PCR, viral studies etc)
Meningitis
• Diagnosis
– CSF Findings :
Opening pressure
Appearance
Cell count & differential
Glucose
Protein
Gram stain & culture
• Opening pressure: high, > 200 mmH20
• Cloudy
• 1000-5000 cells/mm3 with a neutrophil
predominance of about 80-95%
• <40mg/dl and less than 2/3 of the serum
glucose
• Protein elevated
Meningitis
• Diagnosis
– Rapid Tests
• CIE (Counter immunoelectrophoresis/ latex
agglut.)
• PCR
– CT/MRI
• Little role in DIAGNOSIS of menigitis
• Obtain if suspect increased ICP
Meningitis
• Diagnosis
– Additional Tests
• CBC w/ diff
• Blood cultures
• CXR
• Electrolytes and renal function
Meningitis
• Differential Diagnosis
– CNS infections (abscess, encephalitis)
– Viral/ Tb/ Lyme meningitis
– Ricketsial infections
– Cerebral vasculitis
– Subarachnoid hemorrhage
– Neurosyphilis
Meningitis
• Treatment
– Emergent empirical antimicrobial therapy
• Based on age and underlying disease status
– Empiric antibiotic regimines
• Neonates (<3 months)
– Ampicillin plus a third generation cephalosporin
• Children
– Third generation cephalosporin ( alternative -ampicillin
and chloramphenicol)
• Young adults
– Third generation cephalosporin (Ceftriaxone) +
Vancomycin
Meningitis
• Treatment
– Empiric Antibiotic Regimines
• Older adults
– Ampicillin in combination with third generation
ceph.
• Postneurosurgical Pt’s
– Vancomycin plus ceftazidime until cultures are
available
Meningitis
• Treatment
– N. Meningitidis
• High dose Pen G
– S. pneumoniae
• Ceftriaxone
• For areas with high level resistance
– Vancomycin plus third generation cephalosporin
or rifampin
Meningitis
• Treatment
– Gm (-) Enterics
• Third generation cephalosporins
– L. monocytogenes
• Ampicillin
– S. aureus
• Vancomycin or Nafcillin
– S. epidermidis
• Vancomycin
Meningitis
• Treatment
– Duration of Treatment
• Dependent on infecting organism
– Average of 10-14 days
– Gm (-) bacilli for 3 weeks
Meningitis
• Treatment
– Steroids
– Shortly before or along with antibiotics. Do not
give steroids after antibiotic treatment.
– de Gans J, van de Beek D. Dexamethasone in adults with
bacterial meningitis. N Engl J Med. 2002;347:1549-56.
Meningitis
• Prognosis
– Pneumococcal Meningitis
• Associated with the highest mortality rate
– 20-30%
• Permanent neurologic sequelae
– 1/3 of pts
– Hearing loss
– Mental retardation
– Seizures
– Cerebral Palsy
Meningitis
• Vaccinations
– Asplenic pts should have had a
pneumoccocal vaccine prior to their
splenectomy
– Vaccines available for H. influenza
– Prophylaxis for N. meningitidis contacts
• Rifampin
Meningitis
• Conclusion
– Meningitis is an infectious disease
emergency
– Mortality is often high but can be
prevented with appropriate medical
therapy
– If you consider meningitis in your
differential, you are committed to an LP
and empiric antibiotics